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Avoid smoking, vaping and nicotine

Not smoking cigarettes and not using vaping or other nicotine products, which for most people who already smoke means stopping with the help of evidence-based cessation treatment rather than willpower alone.

At a glance

  • Evidence: Stopping smoking at any adult age is followed by substantially lower death rates, with cessation before about 40 recovering most of the lost decade of life expectancy.All-cause mortality and life expectancy · Moderate certainty · Observational association
  • What’s uncertain: This is observational evidence, so it cannot show that stopping smoking causes the whole of the observed difference: people who stop differ from people who continue in ways that cohorts adjust for only partly.
  • First step: Ask a clinician or stop-smoking service about medication and behavioural support; supported quit attempts outperform unsupported ones.
  • Before you try it: Nicotine dependence is a medical problem with effective treatment. All precautions
Read the full takeaway

Mortality evidence

Stopping smoking is the best-evidenced long-term-health action in this catalogue. In the 50-year follow-up of British doctors, men who continued smoking died about 10 years younger than lifelong non-smokers, and cessation at 60, 50, 40 or 30 gained roughly 3, 6, 9 or 10 years of life expectancy respectively; contemporary US cohorts report all-cause death rates around 2.8 times higher in current smokers than in never-smokers, with quitting at any age dramatically reducing them. Larger relative reductions have been recorded in people who already have heart disease or diabetes.

Limits of the evidence

Where the evidence stops is important. Almost all of the mortality evidence is observational, so the size of the benefit for any one person is less certain than the relative risks suggest, and the randomised evidence on getting people to stop shows that unsupported quit attempts mostly fail — about 5 in 100 people given no support or behavioural support only succeed, against about 8 to 10 in 100 using nicotine e-cigarettes — which is why the precautions here point to a clinician or a stop-smoking service rather than to willpower.

Nicotine and quitting

Nicotine is a dependence, not a character flaw. Nicotine vaping does help people quit and the best current synthesis rates that evidence as high certainty against nicotine replacement, but the long-term safety of vaping rests on trials that followed people for at most about two years, and the same reviews record that the evidence on vaping and cancer, cardiovascular disease and developmental outcomes is insufficient or unavailable.

A wordless no-smoking symbol on a cream wallDiscussed byPeter AttiaView statements ↓
Long-term healthVaries · Demanding · Low
Reviewed Sep 23, 2026
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Scientific evidence

What the research shows

Outcome assessments based on research, including its uncertainties and limitations.

All-cause mortality and life expectancy

Finding: Benefit supportedCertainty: Moderatestudies found a benefit from doing this

Evidence basis: observational studies (association, not proof of cause)

Stopping smoking at any adult age is followed by substantially lower death rates, with cessation before about 40 recovering most of the lost decade of life expectancy.

Population: Prospective cohorts of adults: 34,439 male British doctors followed from 1951 to 2001; five pooled contemporary US cohort studies plus two historical cohorts covering participants who reached age 55 or older during follow-up; 503,905 adults aged 60 and older in 25 CHANCES consortium cohorts; and 89 cohort studies of people with diabetes.

Research details

Summary

In the 50-year follow-up of 34,439 male British doctors, men born in 1900-1930 who smoked only cigarettes and continued smoking died on average about 10 years younger than lifelong non-smokers, and cessation at age 60, 50, 40 or 30 gained respectively about 3, 6, 9 or 10 years of life expectancy. Among men born around 1920, prolonged cigarette smoking from early adult life tripled age-specific mortality rates, cessation at 50 halved the hazard, and cessation at 30 avoided almost all of it. Contemporary US data show the relative risks are now similar in women and men: in the 2000-2010 cohorts the relative risk of death from any cause was 2.80 for male current smokers and 2.76 for female current smokers compared with never-smokers, and among men aged 55 to 74 and women aged 60 to 74 all-cause mortality was at least three times as high among current smokers. The same analysis reports that smoking cessation at any age dramatically reduced death rates. Two further syntheses agree on direction: in adults aged 60 and older, former smokers had lower cardiovascular mortality than current smokers with risk decreasing continuously with time since quitting, and in people with diabetes former smokers had lower total mortality than current smokers.

Why this certainty

Rated Moderate rather than Strong. Certainty is not lower because the direction is consistent across independent cohorts spanning five decades and several continents, the dose-response relationship with duration since quitting is graded in the expected direction, and the effect sizes are large. Certainty is not higher because the evidence is entirely observational with self-reported exposure, the comparison is between self-selected groups, and no randomised trial has assigned people to continue or stop smoking for mortality follow-up.

Limitations

This is observational evidence, so it cannot show that stopping smoking causes the whole of the observed difference: people who stop differ from people who continue in ways that cohorts adjust for only partly. Smoking status was self-reported in all of these studies, which misclassifies recent quitters as non-smokers and inflates the apparent benefit of quitting. Reverse causation runs the other way as well, because a new diagnosis often triggers quitting and raises short-term mortality in the quitter group. The British doctors cohort is entirely male and occupationally distinctive, and the US contemporary cohorts are predominantly older adults, so effect sizes in younger or more diverse populations are less certain. The studies compare quitters with continuing smokers rather than randomising people to stop. The two claims in this entry's verdict about vaping are constrained by their own sources rather than by this outcome's cohorts: the Cochrane living systematic review rates nicotine e-cigarettes as high-certainty evidence for quitting against nicotine replacement therapy (RR 1.61, 95% CI 1.23 to 2.12; 11 studies, 4,114 participants) but reports no evidence of serious short-term harm only, with longer and larger trials still needed, and the umbrella review finds the evidence on cardiovascular disease, cancer, development and mental and reproductive health insufficient or unavailable.

Effect estimate

Continued cigarette smoking versus lifelong non-smoking: about 10 years of life lost on average, with cessation at 60, 50, 40 or 30 years recovering roughly 3, 6, 9 or 10 years of life expectancy respectively (34,439 male British doctors, 50-year follow-up); contemporary all-cause mortality relative risk in current versus never smokers approximately 2.80 (men) and 2.76 (women).

Sources for this outcome:

Cardiovascular death and events in people who already have cardiovascular disease or diabetes

Finding: Benefit supportedCertainty: Moderatestudies found a benefit from doing this

Evidence basis: observational studies (association, not proof of cause)

People with existing heart disease or diabetes who stop smoking have roughly a third lower risk of death than those who continue.

Population: People with established disease rather than healthy adults: 20 prospective cohort studies of patients diagnosed with coronary heart disease; 89 cohort studies of patients with diabetes (48 studies with 1,132,700 participants and 109,966 deaths contributed to the total mortality estimate); and 503,905 adults aged 60 and older in 25 CHANCES cohorts, of whom 37,952 died from cardiovascular disease.

Research details

Summary

A systematic review of 20 prospective cohort studies of patients diagnosed with coronary heart disease found a 36 percent reduction in the crude relative risk of mortality for those who quit compared with those who continued smoking (RR 0.64; 95% CI 0.58-0.71), and restriction to the six higher-quality studies barely changed the estimate (RR 0.71; 95% CI 0.65-0.77). The authors concluded that the risk reduction appeared consistent regardless of age, sex, index cardiac event, country, and year of study commencement. In 89 cohort studies of people with diabetes, former smokers were at moderately elevated risk of total mortality (1.19; 1.11-1.28) and cardiovascular mortality (1.15; 1.00-1.32) compared with never smokers, which is to say lower than current smokers, for whom the pooled relative risk was 1.55 (1.46-1.64) for total mortality. In adults aged 60 and older in the CHANCES consortium, cardiovascular mortality hazard ratios were 2.07 (95% CI 1.82 to 2.36) for current smokers and 1.37 (1.25 to 1.49) for former smokers compared with never smokers, with excess risk falling continuously with time since cessation. Post-cessation weight gain does not remove the benefit: in a meta-analysis of nine cohort studies, people who quit and gained weight had lower cardiovascular risk than continuing smokers (RR 0.74, 95% CI 0.66 to 0.83) and those who quit without gaining weight had lower risk still (RR 0.86, 95% CI 0.80 to 0.92), with no heterogeneity between the two groups, and smoking cessation was associated with a lower risk of cardiovascular disease and all-cause mortality regardless of post-cessation weight gain.

Why this certainty

Rated Moderate. The consistency across three independent syntheses in different disease populations, the graded decline in risk with time since quitting, and the fact that restricting to higher-quality studies did not change the estimate all argue against a chance finding. Certainty stops at Moderate because the design is observational throughout, misclassification of smoking status is documented by the authors, and in secondary prevention the act of quitting is entangled with the severity of the underlying illness.

Limitations

All three syntheses pool observational cohorts, so the contrast between quitters and continuing smokers is confounded by the reasons people quit, including new symptoms and diagnoses. The coronary heart disease review notes that many included studies did not adequately address control of confounding or misclassification of smoking status, and that few included large numbers of elderly people, women, ethnic minorities, or patients from developing countries. The CHANCES analysis states that several cohorts lacked repeated smoking assessment, so some current smokers at baseline who subsequently quit were misclassified, which would dilute the contrast. Former smokers never return to never-smoker risk levels in these data, and part of that residual excess is likely to reflect accumulated damage rather than incomplete cessation.

Effect estimate

All-cause mortality after quitting versus continued smoking in patients with coronary heart disease: RR 0.64 (95% CI 0.58-0.71) across 20 cohort studies, and RR 0.71 (95% CI 0.65-0.77) in the six higher-quality studies.; post-cessation weight gain: cardiovascular disease RR 0.74 (95% CI 0.66 to 0.83) among quitters with weight gain and 0.86 (95% CI 0.80 to 0.92) among those without, versus continuing smokers (9 cohort studies)

Sources for this outcome:

What people say

Who discusses this?

Public statements, with positions specific to each source and topic. These views do not determine the scientific evidence assessment.

What the research shows ↑

Practical steps and precautions

How to try it

  1. If you smoke, treat stopping as a treatment rather than a decision: ask a clinician or a stop-smoking service about the medication and behavioural support that suit you — in the randomised evidence reviewed here, supported quit attempts worked better than unsupported ones.
  2. Set a quit date and remove cigarettes, lighters and ashtrays from home, car and workplace on that date rather than cutting down indefinitely. The trials in this record tested stopping rather than indefinite cutting down, so this is editorial advice rather than a tested comparison of the two methods.
  3. Expect more than one attempt. Most people who stop for good have made several previous attempts, so a relapse is information about what support to add next, not a verdict on whether you can stop.
  4. If you vape, use it as a route out of cigarettes with a plan to stop vaping too, and buy regulated nicotine-containing products rather than illicit or unregulated devices; do not use vaping to prolong situations in which you would otherwise be smoking.

Precautions

  • Nicotine dependence is a medical problem with effective treatment. Do not attempt to stop unassisted if you have already tried and relapsed, and do not read this entry as advice to quit cold turkey: ask a clinician or a stop-smoking service about medication, combination nicotine replacement therapy and behavioural support.
  • Do not switch to vaping on the understanding that it is a guaranteed safe alternative. Trials of nicotine vaping followed participants for at most about two years, and reviews conclude that the evidence on vaping and cancer, cardiovascular disease, development, and mental and reproductive health is insufficient or unavailable.
  • Vaping is clearly not harmless for people who do not smoke. There is substantial evidence that nicotine e-cigarettes can cause dependence in non-smokers, and strong evidence that young non-smokers who vape are more likely than non-users to start smoking and to become regular smokers.
  • Protect other people as well as yourself. Secondhand smoke exposure in never smokers is associated with higher all-cause mortality and cardiovascular disease, so keep indoor spaces, and especially homes with children, smoke-free.

References

Mortality in relation to smoking: 50 years' observations on male British doctors.

Doll R, Peto R, Boreham J, Sutherland I · BMJ (Clinical research ed.) · 2004

Prospective cohort study with 50 years of follow-upVerified from full text
Open original source

Impact of smoking and smoking cessation on cardiovascular events and mortality among older adults: meta-analysis of individual participant data from prospective cohort studies of the CHANCES consortium.

Mons U, Müezzinler A, Gellert C, Schöttker B, Abnet CC, Bobak M, de Groot L, Freedman ND, Jansen E, Kee F, Kromhout D, Kuulasmaa K, Laatikainen T, O'Doherty MG, Bueno-de-Mesquita B, Orfanos P, Peters A, van der Schouw YT, Wilsgaard T, Wolk A, Trichopoulou A, Boffetta P, Brenner H · BMJ (Clinical research ed.) · 2015

Individual participant data meta-analysis of 25 prospective cohort studiesVerified from full text
Open original source

Relation of Smoking With Total Mortality and Cardiovascular Events Among Patients With Diabetes Mellitus: A Meta-Analysis and Systematic Review.

Pan A, Wang Y, Talaei M, Hu FB · Circulation · 2015

Systematic review and meta-analysis of prospective cohort studiesVerified from full text
Open original source

Electronic cigarettes and health outcomes: umbrella and systematic review of the global evidence.

Banks E, Yazidjoglou A, Brown S, Nguyen M, Martin M, Beckwith K, Daluwatta A, Campbell S, Joshy G · The Medical journal of Australia · 2023

Umbrella review of major independent reviews plus top-up systematic reviewVerified from full text
Open original source

Electronic cigarettes for smoking cessation.

Lindson N, Livingstone-Banks J, Butler AR, McRobbie H, Bullen CR, Hajek P, Wu AD, Begh R, Theodoulou A, Ma C, Notley C, Rigotti NA, Turner T, Fanshawe T, Hartmann-Boyce J · The Cochrane database of systematic reviews · 2026

Living systematic review and meta-analysis of randomised controlled trialsVerified from full text
Open original source

Mortality risk reduction associated with smoking cessation in patients with coronary heart disease: a systematic review.

Critchley JA, Capewell S · JAMA · 2003

Systematic review of prospective cohort studiesVerified from abstract
Open original source

Smoking Cessation, Weight Gain, Cardiovascular Risk, and All-Cause Mortality: A Meta-analysis.

Wang X, Qin LQ, Arafa A, Eshak ES, Hu Y, Dong JY · Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco · 2021

Systematic review and meta-analysis of cohort studiesVerified from abstract
Open original source

Risk of all-cause mortality and cardiovascular disease associated with secondhand smoke exposure: a systematic review and meta-analysis.

Lv X, Sun J, Bi Y, Xu M, Lu J, Zhao L, Xu Y · International journal of cardiology · 2015

Systematic review and meta-analysis of prospective cohort and case-control studiesVerified from abstract
Open original source

Decrease in risk of lung cancer death in Japanese men after smoking cessation by age at quitting: pooled analysis of three large-scale cohort studies.

Wakai K, Marugame T, Kuriyama S, Sobue T, Tamakoshi A, Satoh H, Tajima K, Suzuki T, Tsugane S · Cancer science · 2007

Pooled analysis of three prospective cohort studiesVerified from full text
Open original source

Influence of smoking cessation after diagnosis of early stage lung cancer on prognosis: systematic review of observational studies with meta-analysis.

Parsons A, Daley A, Begh R, Aveyard P · BMJ (Clinical research ed.) · 2010

Systematic review and meta-analysis of observational longitudinal studiesVerified from full text
Open original source

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Editorial history and review method

Revision 4 · Approved for publication · Codex (publication approval explicitly authorized by site owner; category migration)

Prepared and checked with AI. Publication approval does not imply independent expert review. Request a correction.

Audit correction pass (group 6). Four unsupported claims fixed. (1) Verdict: the unaided-quitting figure ('about 2 to 3 percent of attempts') appears in no retrieved source and was replaced with the retrieved lindson-2026 plain-language figures — about 5 in 100 with no support or behavioural support only, about 8 to 10 in 100 using nicotine e-cigarettes. (2) Implementation 1 and precaution 1: the claim that varenicline and nicotine replacement both raise quit rates above placebo is not tested by any source cited in this record (in lindson-2026, NRT is the comparator arm), so both were reworded to direct readers to a clinician or stop-smoking service and to say only that supported quit attempts worked better than unsupported ones in the randomised evidence reviewed here; varenicline and NRT are still named as things to ask about, which is the treatment-as-dependence framing the record already uses. (3) Card summary: 'Vaping and nicotine replacement both beat willpower alone' is now attributed to vaping only, because the verified estimate (RR 1.75, 95% CI 1.39 to 2.20 versus no support or behavioural support only) is for nicotine e-cigarettes and there is no cited NRT-versus-unsupported-quitting estimate. (4) Implementation 2: 'because the trial evidence is for stopping rather than for gradual reduction' asserted a comparison no cited trial made, and now reads as explicitly editorial advice. cardiovascular-events: the previously orphaned wang-2021-cessation-weight finding is now written into the outcome (post-cessation weight gain did not remove the cardiovascular benefit: RR 0.74, 0.66 to 0.83 with weight gain and 0.86, 0.80 to 0.92 without, versus continuing smokers), and lindson-2026-ecigarettes-cessation and banks-2023-ecigarette-umbrella were removed from this outcome's source list because they supported nothing in it. Every other number and quotation in the record was verified against doll-2004, thun-2013, mons-2015, pan-2015, critchley-2003, lindson-2026, banks-2023, lv-2015, wakai-2007 and parsons-2010 and none was wrong. A second reviewer must re-check: (1) that the certainty ratings are still not inflated — all-cause mortality Moderate and cancer Limited; (2) that the reworded implementation and precaution no longer imply that any specific drug has a placebo-controlled effect, since no such trial is cited; (3) that no sentence claims causation from cohort data, including the new post-cessation weight-gain sentence; (4) that wang-2021-cessation-weight does not collide with the separate wang-2021 record in content/sources.json; and (5) the open question recorded at creation — whether the vaping evidence should become its own outcome, since lindson-2026 and banks-2023 now support prose in the verdict, implementation and precautions but no published outcome. Orphan-source triage: the umbrella review of e-cigarette health outcomes and the Cochrane living review of e-cigarettes for cessation are now cited from all-cause-mortality-and-life-expectancy, which is the outcome carrying the verdict's vaping claims. Both claims - that vaping helps people quit on high-certainty evidence and that the long-term evidence on cancer, cardiovascular disease and development is insufficient - were already in the verdict text but had no citation a reader could follow, because the sources sat outside every outcome's source list. A second reviewer must check that adding these to a mortality outcome does not imply they measured mortality: they did not, and the limitations text now says so explicitly. Publication release 2026-10-04: site owner authorized a bounded AI audit and release of this exact revision. See docs/release-audit-2026-10-04.md for source-check findings and limits. No independent health-professional or peer review is claimed. Category migration 2026-10-04: removed the separate goals field; categories: Long-term health → Long-term health. Research assessments, sources, guidance, precautions, and evidence review dates are unchanged. This revision awaits publication approval; no new evidence review is claimed. Publication approval 2026-10-04: site owner explicitly accepted all current category-migration revisions for deployment and requested that remaining limitations be retained in docs/content-review-backlog.md. Approval applies to this exact content revision. No new evidence review, independent expert review, or clinical validation is claimed; existing precautions and disclosures remain in effect.